Regulation of gluconeogenesis is thought to be controlled at the P-enol-pyruvate carboxykinase step. Long term regulation may occur by way of induction of this enzyme, however the short term regulation has not been described. A purpose of these studies is to test the hypothesis that metal ions are responsible for the short term regulation. Steady-state kinetic studies and NMR studies will be used to investigate the role of the metal ion in catalysis. The partial reactions of oxaloacetate decarboxylation and GTP-GDP exchange will be used to investigate the kinetic and catalytic mechanism of the enzyme. The prescence of an inhibitory factor from cytosol will be further investigated for its regulatory potential.